[ubuntu-cloud] Ubuntu cloud image '-root.tar.gz' content changes

[Scott Moser]

On Tue, 29 Oct 2013, Robert Collins wrote:

> On 29 October 2013 07:46, Scott Moser <smoser at ubuntu.com> wrote:
> > Hi all,
> >
> > tldr;
> >   As we look forward to the 14.04 deliverable of cloud images, we're wanting
> >   to reduce legacy formats and streamline those that we have.
> >
> >   If you're a consumer of the '-root.tar.gz' file then read on.
> >   The change suggested here will *only* affect the -root.tar.gz file.
> >
> > We make several formats of images available on cloud-images.ubuntu.com.
> > The one relevant to this mail is the '-root.tar.gz'.  This is essentially
> > a 'tar -cSpzf - /' of the contents of /.
> >
> > The changes we've just made to trusty are to remove the kernel and
> > bootloader packages before creating the tarfile.  Essentially doing a
> > 'apt-get --purge remove "linux-*" "grub-*"' before packaging.
> >
> > The reasoning for this is
> > a.) the images will then be more similar to the ubuntu core tar files at
> >     http://cdimage.ubuntu.com/ubuntu-core/releases/12.04/release/
> > b.) the images are primarily used for lxc, where a kernel and bootloader
> >     are not necessary or used.
> > c.) there is a ~25M reduction in the size of the tarball, and a 100M+
> >     reduction in the size of the extracted root.
> >
> > I'm interested in hearing feedback from anyone using these images that
> > would be [negatively] affected by the proposed change.
>
> Hi, we use those images (the root.tar.gz) ones for diskimage-builder
> in OpenStack. We build both vm and baremetal images from them, and
> currently assume that there is a kernel in them (but we do remove grub
> from them early on). Overall I think this is probably a good idea, but
> we'll need to fixup our code to be a bit more explicit about whether
> the output is for a vm or physical machine.

-root.tar.gz != tar.gz

The '.tar.gz' files have a unpartitioned disk image and a kernel in them.
ie:
$ tar -tvzf saucy-server-cloudimg-amd64.tar.gz
-rw-r--r-- root/root 1476395008 2013-10-27 03:37 saucy-server-cloudimg-amd64.img
-rw-r--r-- root/root    5600016 2013-10-27 03:36 saucy-server-cloudimg-amd64-vmlinuz-generic
-rw-r--r-- root/root      91708 2013-10-27 03:37 saucy-server-cloudimg-amd64-loader
-rw-r--r-- root/root    2949120 2013-10-27 03:37 saucy-server-cloudimg-amd64-floppy
-rw-r--r-- root/root       3300 2013-10-27 03:33 README.files

The -root.tar.gz files have actual filesystem contents:

$ tar tvzf saucy-server-cloudimg-amd64-root.tar.gz
drwxr-xr-x root/root         0 2013-10-27 03:36 bin/
-rwxr-xr-x root/root    122096 2013-01-17 07:03 bin/mv
-rwxr-xr-x root/root    110088 2013-01-17 07:03 bin/ls
lrwxrwxrwx root/root         0 2012-08-15 10:41 bin/sh.distrib -> dash
-rwxr-xr-x root/root     31864 2012-11-29 15:32 bin/fuser

I think you were using the .tar.gz files. not sure.